Golf club assembly having interchangeable inner flex members

ABSTRACT

An adjustable shaft for golf clubs comprises a hollow elongated shaft fixed to a club head. The shaft is open at one end to receive an elongated flex member. The flex member is characterized by a predetermined degree of flexibility along its length to impart a specific reflex to the shaft along its length. Adjustability of flex along the club shaft enables the golfer to determine the degree of shaft flexibility to suit his specific requirements.

United States Patent 1191 Shulkin Sept. 3, 1974 GOLF CLUB ASSEMBLYHAVING INTERCHANGEABLE INNER FLEX MEMBERS [76] Inventor: Robert A.Shulkin, 24122 E.

Sprague, Liberty Lake, Wash. 99019 22 Filed: July 9,1973

21 Appl. No.2 377,526

[52] US. Cl. 273/194 R, 273/80 B, 273/162 R [51 1 Int. Cl A63b 69/36[58] Field of Search.... 273/80 R, 80 B, 80 D, 77 R, 273/77 A, 81.2, 32R, 162 R, 162 F, 193 R,

194 R,'-35 R; 43/18 R [56] References Cited UNITED STATES PATENTS1,494,530 5/1924 Cook 43/18 1,686,323 10/1928 Von Der Heyde 273/162 F1,994,069 3/1925 Fletcher 273/80 B 2,801,106 7/1957 Koehler 273/80 B X2,822,174 2/1958 Brandon 273/77 A 3,180,308 4/1965 Carrol et al. 273/193R X 3,310,903 3/1967 Binvignat 3,461,593 8/1969 Martuch 61 al 273/80 B xFOREIGN PATENTS OR APPLICATIONS 25,196 11/1911 Great Britain 43/18 R690,270 4/1953 Great Britain 273/80 B Primary ExaminerRichard C. PinkhamAssistant Examiner-Richard J. Apley Attorney, Agent, or Firm-Wells, St.John & Roberts [57] ABSTRACT 2 Claims, 18Drawing Figures BACKGROUND OFTHE INVENTION This invention relates broadly to the field of golfingequipment and more particularly to an adjustable flexible shaft assemblyfor golf clubs which allows the golfer to select a proper shaftstructure to suit his needs.

It has been found that golfers with fitted clubs tend to hit the ballfurther and more accurately than do those golfers whose clubs arentfitted to their golfing style and physical capabilities. It isunderstandably desirable that a golfer obtain clubs that-suit his ownpersonal requirements.

The present method of fitting individuals with golf clubs having aproper amount of flex along the club shaft is simply to supply thegolfer with a number of clubs, each having a different degree offlexibility along the length of the shaft. Obviously this method israther expensive for the golf equipment dealer who must stock a largenumber of clubs, only to have one specific club purchased. It is alsosomewhat tiresome for the golfer being fitted to experiment with a largenumber of individual clubs before selecting the one best suited tohimself. I

The apparatus of the present invention serves to eliminate the aboveproblems by providing a single golf club that includes a shaft assemblywith flex adjusting means for selectively changing the flexibility ofthe shaft along its length. With the present invention, the golfer needonly practice with a single club and the equipment dealer need onlypurchase one club for fitting purposes. Once the golfer selects a propershaft flex, he may then specify that particular degree of flex with hisorder for fitted clubs.

SUMMARY OF THE INVENTION The apparatus of the present inventioncomprises a golf club shaft assembly formed of an elongated shaft havinga first end mountable to a golf club head. The second end of the shaftis spaced longitudinally from the first end and includes a handgripmounted thereto. Flex adjusting means is provided to be mounted to theshaft. The flex adjusting means provides a selectively variable degreeof flexibility along the length of the shaft.

It is a first object of my invention to provide an adjustable shaftassembly for golf clubs that requires the use of only one club todetermine individual requirements of golfers for aspecific degree ofgolf club shaft flexibility.

An additional object of my invention is to provide such an adjustableshaft that is inexpensive to manufacture.

A further object of my invention is to provide such an adjustable shaftthat may be combined with other adjusting features of a golf club suchas club head weight and loft angle.

An additional object of my invention is to provide such an adjustableshaft that may be selectively varied to match any one of severalstandard degrees of flexibility presently utilized in quality golfclubs.

These and other objects and advantages will become evident upon readingthe following disclosure which, taken with the accompanying drawings,describes a preferred and alternate form of my invention.

A BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational viewof a golf club utilizing the shaft of the present invention;

FIG. 2 is an elevational sectioned view taken along line 2-2 in FIG. 1';

FIG. 3 is an elevational sectioned view taken along line 3-3 in FIG. 1;

FIG. 4 is a cross sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is a cross sectional view taken along line 55 in FIG. 1;

FIG. 6 is an elevational view of a flex member;

FIG. 7 is a fragmentary pictorial view of a section of the golf clubshaft;

FIG. 8 is an elevationally sectioned fragmentary view of a golf clubshaft embodying the second form of my invention;

FIG. 9 is an isometric view of a portion of the second form of myinventionillustrated in FIG. 8;

FIG. 10 is a cross sectional view taken along line l0l0. in FIG. 8; i

FIGS. 11-14 are elevational plan views showing various adjustmentpositions of the flexadjusting means of the second embodiment; and

FIGS. 15-18 are cross sectional views illustrating operational positionsof the flex adjusting means.

DETAILED DESCRIPTION OF A PREFERRED AND ALTERNATE EMBODIMENT A golf clubutilizing the adjustable shaft assembly of the preferred and alternateforms of the present invention is illustrated in FIG. 1 and isdesignated by the reference numeral 10. The golf club 10 includes a headportion 11 affixed to a shaft 12 which extends from a first or lower end13 to a second or upper end 14 about a longitudinal axis YY. Adjacentthe upper end 14 of i the shaft 12 is a handgrip 15.

Golf club shafts such as the one illustrated in the drawings ofteninclude a series of flex steps 16 which, along with the thickness of theshaft walls, determine the degree of flexibility of the shaft along itslength. The flex steps 16 are circular in cross section and extend fromthe lower shaft end 13 to the lower end of the handgrip 15. Theyincrease in cross-sectional diameter from a smaller diameter adjacentthe lower end 13 to a larger diameter adjacent the handgrip 15.

. The shaft 12 is hollow along its length to receive one of a series offlex members of the preferred form for determining the degree offlexibility along the length of the shaft 12. One flex member 21 is bestillustrated in FIGSQ2, 3, and 6. It includes flex steps 22 (FIGS. 3 and6) that are complementary to the flex steps 16 extending longitudinallyalong the shaft 12.

The members 21 are received within a longitudinal cavity formed in theshaft 12 through an opening 17 formed within the upper shaft end 14. Theinside of the shaft 12 adjacent opening 17 is provided with twist lockslots 26 (FIG. 7) which are designed to receive complemental-y lugs 25extending from the upper end of each flex member 21. Lugs 25 and slots26 define a fastening means which serves to securely fasten the flexmember 21 within the shaft 12. Flex member 21 may be selectivelyinserted or removed from the shaft 12 by simply disengaging the lugs 25from the slots 26 by turning a cap 27 fixed to the top of the flexmember 21.

It is intended that the flex adjusting means of the preferred form becomprised of a plurality of flex members similar to the member 21 shownin the drawings. Each flex member would then be characterized by aprescribed wall thickness, designated in FIG. 3 by the distance X. Byvarying the wall thickness X with respect to the thickness of the shaft12, I am able to selectively adjust the degree of flexibility of theshaft 12 along its length. Since golf club shafts are conventionallyavailable in several standard flex characteristics, I intend to producethe flex members with varying wall thicknesses X so that when combinedwith the wall thickness of the shaft 12, each member will impart alongitudinal rigidity to the shaft 12 which corresponds to one of theseveral standard degrees of flexibility. Therefore, once a golfer hasdetermined his specific requirements for a specific degree of shaftflexibility, he may then specify that degree of flexibility in orderinghis fitted clubs. It is also possible to construct each insert member ofdifferent materials having varying physical properties to produce thedesired degree of flex for each flex member.

The second or alternate form of the present invention is illustrated inFIGS. 8-18. In this particular embodiment, the flexibility of the shaft12 is determined by the angular position of the flex adjusting meansrelative to the shaft axis YY. The flex adjusting means of the alternateform is comprised of an outer flex member 28 and an inner flex member30. Both outer member 28 and inner member 30 are received within theshaft 12 for free pivotal movement about the longitudinal shaft axis YY.

Flex members 28 and 30 include longitudinal elongated slots 31, 32respectively that extend transversely through each member. The slots 31,32 cause the flex members to have varying degrees of flex along theirlengths with respect to the angular positions of the slots relative tothe plane of the golf club face which is indicated by a reference plane36 in FIGS. 11-18. By selectively rotating the flex members within theshaft 12 about the axis YY, the user is able to determine any one offour different flex settings, each setting closely corresponding to aconventional flexibility standard. A fifth setting is made possiblesimply by removing the flex members from the shaft 12. The shaft 12alone is intended to have the flex characteristics necessary for thehighest standard degree of shaft flexibility currently available.

As shown in FIG. 8, the outer flex member 28 is held within the shaft 12by cap 33 at the upper end of handgrip 15. The cap 33 facilitatesselective angular adjustment of the outer flex member 28 about the axisYY. Angular movement of the outer flex member 28 is limited by a pin andgroove assembly operatively connecting the shaft 12 to the cap 33. Adiametrically opposed set of pins or lugs 34 protrude radially outwardfrom the shaft 12 to engage complementary grooves 35 (FIG. 9) formedwithin the cap 33. One groove 35 is illustrated in FIG. 9. It extendsannularly about the inside periphery of the cap 33 to include an angleof approximately 90 between upturned ends 37. The upturned ends 37 allowthe outer flex member 28 to be locked in a prescribed angularorientation with respect to the club face plane 36. Adjustment of theangular position of the outer flex member 28.is accomplished by liftingupwardly on cap 33 to dislodge the lugs 34 from the upturned ends 37 ofgrooves 35. The cap 33 may then be pivoted about the axis YY to theupturned ends 37 adjacent the opposite ends of the grooves 35. Angularpositions of the outer flex member 28 are illustrated in FIGS. 16 and17.

The cap 33 includes an upwardly facing opening 38 through which an indexknob 40 extends to rotatably mount the inner flex member 30 within theouter flex member 28. The knob 40 may be angularly indexed about theaxis YY of the shaft to position the inner flex member 30 between twoangular positions relative to the club face plane 36. These positionsare illustrated in FIGS. 16 and 17.

The cap 33 and knob 40 are independently operable to allow the inner andouter flex members to be angularly adjusted independently or together.

- FIGS. 11-14 show the cap 33 in plan view to illustrate four possiblesettings of the cap 33 and knob 40 that align the inner and outer flexmembers angularly with respect to the plane 36 to determine fourseparate flex settings as shown in FIGS. 15-18 respectively. The cap 33is provided with indicia in the form of a plus sign 41 and a minus sign42 which indicate the angular position of the outer flex member 28 whenaligned with the plane 36. The setting shown in FIGS. 12 and 13indicates that the outer flex member 28 is in an angular position withinthe shaft 12 to cause the greatest degree of longitudinal rigidity alongthe shaft that may be obtained by combining the flex member 28 and theshaft 12.

The minus sign 42 when aligned with the club face plane 36 indicates theangular position of the outer flex member. 28 that is shown in FIGS. 17and 18. By adjusting the cap to this angular position, the slot 31 isaligned with the club face plane 36, thereby increasing flexibility ofthe shaft along its length.

The knob 40 is also provided with an indicator in the fonn of a smallplus sign 43. When the knob 40 is adjusted to the position shown in FIG.11 with the small plus sign 43 aligned with the club face plane 36, theresulting angular position of the inner flex member 30 is as shown inFIGS. 15 and 17. In this position the slot 32 of the inner flex member30 is aligned substantially perpendicular to the plane 36 so that theinner flex member 30 provides a maximum degree of rigidity to the shaft12.

By turning the knob 40, to the position shown in FIG. 12, the angularposition of the inner flex member 30 is shifted 90 from the positionshown in FIGS. 15 and 17 to the position shown in FIGS. 16 and 18. Inthis position the slot 32 is aligned with the plane 36 to allow agreater degree of flex along the length of shaft 12.

The outer flex member 28 and inner flex member 30 may be adjusted to anyof the four positions illustrated to produce any of the 4 of flex commonto the standards utilized in conventional golf clubs. The setting thatprovides the greatest degree of longitudinal rigidity along the shaft 12is made by angularly adjusting the knob 40 and cap 33 with respect tothe plane 36 as shown in FIG. 11 so that the two plus signs 41 and 43align with plane 36. The corresponding positions of the outer and innerflex members 28, 30 respectively is illustrated in FIG. 15. In thisposition both the slots 31 and 32 are aligned substantiallyperpendicular to the club face plane 36, thereby imparting the greatestpossible amount of longitudinal rigidity to the outer shaft 12.

FIG. 12 shows a second setting wherein the knob 40 has been pivoted 90to move the inner flex member 30 to a position wherein the slot 32 issubstantially aligned with the plane 36 (FIG. 16). This positionproduces a different degree of flex along the shaft 12 that correspondsto a slightly more flexible setting than that illustrated in FIG. 11. Aslightly more flexible setting is accomplished by turning the knob 40back to align the plus sign 43 with plane 36 and then turning the cap 33to align the minus sign 42 with the plane 36 (FIG. 13). The resultingangular positions of the flex members 28 and 30 are illustrated in FIG.17.

Finally, the flex members 28 and 30 may be aligned to present both slots31 and 32 in alignment with the plane 36 (FIG. 18) to allow the greatestdegree of flexibility along the shaft 12 with the flex members heldtherein. The corresponding setting of the knob 40 and cap 33 isillustrated in FIG. 14, wherein the minus sign 42 is aligned with theplane 36 and the plus signs 41 and 43 are aligned with one another.

As described above, the fifth flex setting may be obtained by removingthe flex members 28 and 30 from the outer shaft 12 to allow the greatestdegree of flexibility along the length of the shaft 12.

It is intended that the present invention be utilized with golf clubheads 11 having other adjusting features utilized in golf clubs forfitting purposes. Such club heads might include means for adjusting theclub head weight as well as the loft or angle of the club face. Whenused with such a combination, the golfer may be personally fitted for aspecific club through the provisions for adjusting the loft angle, clubhead weight, and the degree of shaft flex, by simply making variousadjustments to a single golf club.

It may become obvious from the above description and attacheddrawings'that various changes may be made therein without departing fromthe intended scope of this invention. Therefore, only the followingclaims are intended to define this invention.

What I claim is:

1. A golf club assembly for enabling a golfer to select the appropriateshaft flexibility in a golf club according to the golfers style andphysical capabilities, comprismg:

a test golf club having an axially hollow, elongated,

flexible shaft with a club head fixed to a lower end thereof and a handgrip fixed to an upper open endthereof;

a plurality of interchangeable elongated flex members, each having adifferent predetermined flexibility and an exterior contourcomplementary to the hollow interior of the flexible shaft for selectiveinsertion into the interior of the flexible shaft through the upper endwith the resultant flexibility being a function of the combinedflexibility of the shaft and the selected inserted flex member; and

releasable fastening means engageable between the shaft and the insertedflex member for releasably securing the inserted flex member in theflexible shaft while the test golf club is being utilized.

2. The golf club shaft set out in claim 1 wherein said fastening meanscomprises complementary engageable sections on the shaft and flex memberpositioned on said shaft and flex member to securely engage said flexmember within said shaft.

1. A golf club assembly for enabling a golfer to select the appropriateshaft flexibility in a golf club according to the golfer''s style andphysical capabilities, comprising: a test golf club having an axiallyhollow, elongated, flexible shaft with a club head fixed to a lower endthereof and a hand grip fixed to an upper open end thereof; a pluralityof interchangeable elongated flex members, each having a differentpredetermined flexibility and an exterior contour complementary to thehollow interior of the flexible shaft for selective insertion into theinterior of the flexible shaft through the upper end with the resultantflexibility being a function of the combined flexibility of the shaftand the selected inserted flex member; and releasable fastening meansengageable between the shaft and the inserted flex member for releasablysecuring the inserted flex member in the flexible shaft while the testgolf club is being utilized.
 2. The golf club shaft set out in claim 1wherein said fastening means comprises complementary engageable sectionson the shaft and flex member positioned on said shaft and flex member tosecurely engage said flex member within said shaft.